Battery lockout override logic for a battery management system

ABSTRACT

Disclosed herein are battery management systems and methods for activating battery override logic for a battery management system to provide a power path to a battery pack. A method of activating battery override logic for a battery management system may comprise detecting a predetermined key toggle sequence performed in a predetermined amount of time or detecting an override message received from a CAN bus. The method may further comprise determining if the last override turn-on sequence was requested more than a predetermined amount of time ago, confirming that the override is configured for the contactor, and turning on the contactor to provide a power path to the battery pack for a limited predetermined amount of time. An exemplary predetermined toggle sequence may comprise on-off-on-off-on performed within 10 seconds. An exemplary override message from the CAN bus may be initiated by a user having a key, code, or access card.

PRIORITY

The present application is related to, and claims the priority benefitof U.S. Provisional Patent Application Ser. No. 62/770,771, filed onNov. 22, 2018, the contents of which are incorporated into the presentdisclosure directly and by reference in their entirety.

BACKGROUND

Lithium battery systems have battery management systems (BMS) whichmonitor the battery usage and charge state of the battery pack. The BMSwill shut off the power path to the battery pack by opening a contactorwhen the battery pack charge is very low, or when there are otherproblems with the battery pack, such as overheating, etc. Shutting offthe power path to the battery pack can sometimes leave the equipment(utilizing the battery pack) stranded in poor locations, such as faraway battery chargers, which are needed to get the battery charged andthus, the equipment operating again.

In the past, when equipment ran out of battery power at an undesirablelocation, far away from a battery charger, the equipment would need tobe towed back to the maintenance area, or a spare battery would need tobe called for and then driven out to the equipment, or a remote batterycharger may have been called for and then driven out to the equipment,or BMS lockout may have been manually overridden by using specialsoftware to change the BMS operation, but all of these alternativeoptions to get the equipment running again took a lot of time andeffort, which resulted in lost profits.

It would thus be desirable to add control logic to the BMS, to allow theuser to manually override the BMS shut down for a short, monitoredperiod of time, to allow the equipment to be returned to the charger ormaintenance area as needed. This avoids the problem of leaving large,bulky, or heavy equipment stranded in an undesirable location far awayfrom the battery charging area.

BRIEF SUMMARY

A first embodiment of a method of activating battery override logic fora battery management system to provide a power path to a battery pack,comprises detecting a predetermined key toggle sequence or detecting anoverride message received from a CAN bus; determining that the lastoverride turn-on sequence was requested more than a predetermined amountof time ago; confirming that the override is configured for thecontactor; and turning on the contactor to provide a power path to thebattery pack for a limited predetermined amount of time.

A second embodiment of a method of deactivating battery override logicfor a battery management system to shut down a power path to a batterypack, comprises determining if battery override logic has been on formore than a predetermined amount of time, or determining if dischargecurrent is more than a predetermined value, or determining if chargecurrent is more than a predetermined value; and turning off thecontactor to shut down the power path to the battery pack if any one ofthe three determinations has been met.

A first embodiment of a battery management system for activating batteryoverride logic to provide a power path to a battery pack, wherein thebattery management system comprises override control logic configured todetect a predetermined key toggle sequence or detect an override messagereceived from a CAN bus; determine that the last override turn-onsequence was requested more than a predetermined amount of time ago; andconfirm that the override is configured for a contactor; and a batterypack operably coupled to the contactor, wherein when the overridecontrol logic is configured for the contactor, the contactor isconfigured to provide a power path to the battery pack for a limitedpredetermined amount of time.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed embodiments and other features, advantages, anddisclosures contained herein, and the matter of attaining them, willbecome apparent and the present disclosure will be better understood byreference to the following description of various exemplary embodimentsof the present disclosure taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 illustrates a flowchart for the battery override logic operatingin a “turn ON” sequence; and

FIG. 2 illustrates a flowchart for the battery override logic operatingin a “turn OFF” sequence.

As such, an overview of the features, functions and/or configurations ofthe components depicted in the various figures will now be presented. Itshould be appreciated that not all of the features of the components ofthe figures are necessarily described and some of these non-discussedfeatures (as well as discussed features) are inherent from the figuresthemselves. Other non-discussed features may be inherent in componentgeometry and/or configuration. Furthermore, wherever feasible andconvenient, like reference numerals are used in the figures and thedescription to refer to the same or like parts or steps. The figures arein a simplified form and not to precise scale.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of this disclosure is thereby intended.

The present disclosure includes various battery control logic operationsfor battery management systems (BMS), and methods and sequences ofturning the battery control logic on and off. The battery override logictaught herein allows a user to manually override the BMS shut down for ashort, monitored period of time, to provide a limited amount of power tothe battery pack so that the equipment can be returned to the charger ormaintenance area as needed. This battery override logic is intended toefficiently aid employees in operating large equipment (such as cranes,jacks, forklifts, etc.) utilizing BMS, such as in larger fulfillmentwarehouse operations etc., to prevent leaving large equipment strandedin undesirable locations or far away from battery chargers.

Lithium battery systems have battery management systems (BMS) whichmonitor the battery usage and/or charge state of the battery pack. If abattery pack becomes overly discharged (i.e., very low battery), the BMSwill shut off the power output to protect the battery pack from damage.Similarly, if the battery pack is overly charged (i.e., battery becomestoo charged), then the BMS will also shut down the charge path toprotect the battery pack from damage. Additionally, the BMS may alsoshut down the power path to the battery pack due to other detectedconditions, such as temperature limits, cell imbalances, shock level,communication issues, or possible internal BMS errors. When the batterypower path is shut down, for any of these reasons, it can strand theequipment in poor locations, cause disruptions in the work flow, orpossibly leave equipment in dangerous locations.

To eliminate the need for outside/maintenance support to get theequipment moving again, the BMS has been designed to incorporate batterycontrol override logic which will allow the battery power shut down tobe “overridden,” allowing a “limp home” mode of operation of the batterypack. This “limp home” mode may provide a limited amount of batterypower, at a reduced current, for a limited or predetermined amount oftime, to allow the equipment to be moved to a better location forcharging or maintenance.

The BMS may detect a request for the battery override logic in severalways. The BMS may detect an override request by sensing multiple keysequence toggles (such as on-off-on-off-on) of the battery power switchin a predefined period of time, such as within 10 seconds, or mayreceive a request for override sent via a serial bus communication orCAN bus, for example. The request for override from the CAN bus, may bedone manually, such as by entering a predetermined code, key, or accesscard, for example. Additionally, the battery override logic may alsoverify that the last override request was performed more than 30 minutesago, to prevent the override logic from being used multiple times in arow, thus preventing damage to the battery pack. When the batteryoverride logic request is received, the BMS will close the powercontactor, allowing the battery's power path or contactor to flow to theequipment for just a few more minutes, thus providing battery power tothe equipment for the limited time period in a “limp home” mode.However, in the “limp home” or limited mode of operation, the BMS mayalso set a timer to only allow power output for a programmable orpredetermined amount of time, such as 2 minutes, for example, to preventany major or permanent damage to the battery pack.

Additionally, the battery override logic may allow only a reducedcurrent output as compared to normal current output/operation. Forexample, the battery override logic may only allow a reduced current of50 amps, as compared to a normal current of 200 amps supplied to thebattery pack, or a predetermined percentage of only 25% of normaloperating current. These predetermined parameters are exemplary only forthe purposes of illustration herein and of course, other currents orpercentages of operating current may be used herein. These predeterminedparameters can also be preprogrammed, depending on the type or size ofbattery pack and the type of equipment. In addition, the allowed currentlevel output and times can be predetermined or preprogrammed dependingupon the reason for the override. For example, depending upon if theoverride is for battery pack overcharge, or over discharge (i.e. verylow battery), the allowed current level and times can be predeterminedand preprogrammed to help prevent any major or permanent damage to thebattery pack, while still allowing a few extra minutes of operatingpower (i.e., power path to the battery) to safely return the equipmentto a move convenient area or battery charging location.

For example, a forklift driver may continue to operate his forklift(i.e., equipment utilizing a battery pack) after the battery dischargeindicator (aka BDI) reflects a low battery. In this case, the forkliftdriver has discharged the lithium battery below the low voltagethreshold to the point where the BMS shuts off the battery to protectagainst damage. Once the power to the battery pack is shut off, theforklift is now stranded away from the charging area or maintenance areaand can no longer move. In this case, maintenance can then operate thebattery override logic taught herein to allow enough current and powerto flow to the battery to drive the forklift back to the charger.

FIG. 1 is a flowchart 100 illustrating the battery override logic whenthe override is being activated, or operating in the “turn ON” sequence.As shown in the flowchart 100, the battery override logic turn ONsequence can begin by detecting 102 a key toggle, such as anon-off-on-off-on sequence within a predefined period of time (such as“x” minutes of time). Alternatively, the battery override logic turn ONsequence can also begin by detecting 104 an override message receivedfrom a serial bus connector, or CAN bus. If either condition 102 or 104is detected/received, and the last override turn ON 106 was more than apredetermined number of minutes ago (such as “x” minutes ago), then thenext step of flowchart 100 will ask if the above condition is true 108.If the above condition 108 is not true (i.e., “no” as shown in flowchart100), then the override logic will not turn on the contactor and thebattery pack will remain in its previous or shut off state. If the abovecondition 108 IS true (i.e., “yes” as shown on flowchart 100), then thenext step will be to determine 110 if the override is configured for thecontactor. If the override is not configured for the contactor (i.e.,“no” as shown on flowchart 100) then the contactor control will be basedupon mapped or predetermined control logic. If the override isconfigured for the contactor (i.e., “yes” on the flowchart 100) then thecontactor will be turned on to provide a power path to the battery, asshow at final step 112.

FIG. 2 is a flowchart 200 illustrating the battery override logic whenthe override is operating in the “turn OFF” sequence. As shown in theflowchart 200, the battery override logic turn OFF sequence can beginunder three different conditions 202, 204, and/or 206. The batteryoverride logic turn OFF sequence can begin if: 1) the override is on formore than a predetermined amount of time (such as “x” seconds orminutes) 202; 2) the discharge current is more than a predeterminedconfigured value 204; and/or 3) if the charge current is more than apredetermined configured value 206. If any of the three conditions 202,204, and/or 206 is NOT true 208 (i.e., “no” as shown on flowchart 200),then the battery and contactor will remain in its previous state 210. Ifany of the three conditions 202, 204, and/or 206 IS true (i.e., “yes” asshown on flowchart 200), then the contactor will be turned off 212 andthus, the power path to the battery pack will be turned off.

While various embodiments of devices and systems and methods for usingthe same have been described in considerable detail herein, theembodiments are merely offered as non-limiting examples of thedisclosure described herein. It will therefore be understood thatvarious changes and modifications may be made, and equivalents may besubstituted for elements thereof, without departing from the scope ofthe present disclosure. The present disclosure is not intended to beexhaustive or limiting with respect to the content thereof.

Further, in describing representative embodiments, the presentdisclosure may have presented a method and/or a process as a particularsequence of steps. However, to the extent that the method or processdoes not rely on the particular order of steps set forth therein, themethod or process should not be limited to the particular sequence ofsteps described, as other sequences of steps may be possible. Therefore,the particular order of the steps disclosed herein should not beconstrued as limitations of the present disclosure. In addition,disclosure directed to a method and/or process should not be limited tothe performance of their steps in the order written. Such sequences maybe varied and still remain within the scope of the present disclosure.

The invention claimed is:
 1. A method of activating battery overridelogic for a battery management system to provide a power path to abattery pack, comprising: detecting a predetermined key toggle sequenceor detecting an override message received from a CAN bus; determiningthat the last override turn-on sequence was requested more than apredetermined amount of time ago; confirming that the override isconfigured for the contactor; and turning on the contactor to provide apower path to the battery pack for a limited predetermined amount oftime, wherein turning on the contactor to provide a power path to thebattery pack for a limited predetermined amount of time provides enoughpower to operate a piece of equipment during the limited predeterminedamount of time to allow the piece of equipment to be moved to a safelocation or battery charging area.
 2. The method of claim 1, wherein thepredetermined key toggle sequence is performed in a predetermined amountof time.
 3. The method of claim 2, wherein the predetermined key togglesequence is on-off-on-off-on performed within a time period of 10seconds.
 4. The method of claim 1, wherein the power path to the batterypack is at a reduced current, as compared to normal battery power pathoperations.
 5. The method of claim 1, wherein the power path to thebattery pack is at a reduced rate of 25% of a normal battery power pathoperations.
 6. The method of claim 1, wherein determining that the lastoverride turn-on sequence was requested more than a predetermined amountof time ago, comprises more than 30 minutes ago.
 7. The method of claim1, wherein the limited predetermined amount of time of turning on thecontactor to provide a power path to the battery pack comprises twominutes.
 8. The method of claim 1, wherein the override message receivedfrom the CAN bus may be done manually using a predetermined code, key,or access card.
 9. A method of deactivating battery override logic for abattery management system to shut down a power path to a battery pack,comprising: determining if battery override logic has been on for morethan a predetermined amount of time, or determining if discharge currentis more than a predetermined value, or determining if charge current ismore than a predetermined value; and turning off the contactor to shutdown the power path to the battery pack if any one of the threedeterminations has been met, wherein the predetermined amount of timeallows the battery pack to provide enough power to operate a piece ofequipment for the predetermined amount of time to allow the piece ofequipment to be moved to a safe location or battery charging area. 10.The method of claim 9, where determining if the battery override logichas been on for more than a predetermined amount of time comprises 5minutes.
 11. The method of claim 9, where determining if the batteryoverride logic has been on for more than a predetermined amount of timecomprises 2 minutes.
 12. The method of claim 9, wherein determining ifdischarge current is more than a predetermined value comprises adischarge current value of 50 A.
 13. The method of claim 9, whereindetermining if charge current is more than a predetermined valuecomprises a charge current value of 50 A.
 14. The method of claim 9,wherein turning off the contactor to shut down the power path to thebattery pack prevents damage to the battery pack.
 15. A batterymanagement system for activating battery override logic to provide apower path to a battery pack, wherein the battery management systemcomprises: override control logic configured to: detect a predeterminedkey toggle sequence or detect an override message received from a CANbus; determine that the last override turn-on sequence was requestedmore than a predetermined amount of time ago; and confirm that theoverride is configured for a contactor; and a battery pack operablycoupled to the contactor, wherein when the override control logic isconfigured for the contactor, the contactor is configured to provide apower path to the battery pack for a limited predetermined amount oftime, wherein configuring the contactor to provide a power path to thebattery pack for a limited predetermined amount of time, provides enoughpower to operate a piece of equipment for a limited predetermined amountof time to allow the piece of equipment to be moved to a safe locationor battery charging area.
 16. The system of claim 15, wherein thepredetermined key toggle sequence is performed in a predetermined amountof time.
 17. The system of claim 16, wherein the predetermined keytoggle sequence is on-off-on-off-on performed within a time period of 10seconds.
 18. The system of claim 15, wherein the power path to thebattery pack is at a reduced current, as compared to normal batterypower path operations.
 19. The system of claim 15, wherein determiningthat the last override turn-on sequence was requested more than apredetermined amount of time ago, comprises more than 30 minutes ago.